Many lamps, and particularly discharge lamps such as fluorescent lamps, low-voltage lamps such as halogen incandescent lamps designed for operation of voltages below network voltages use accessory operating or accessory circuits. They include circuit elements designed to convert electrical power derived from a standard outlet plug, for example 110/220 V, 60/50 Hz, to the required voltage and frequency characteristics of electrical energy for optimum operation of the lamp for which the circuit is designed. This circuit, usually retained on a circuit board, has to be placed in a housing, provided with connections for energy supply from a network as well as connections for the lamp itself. The housing can be external of the lamp and, for example, be a component of a light fixture or luminaire, to supply one or more electric lamps with electrical energy at the required voltage, current and frequency characterists.
The operating circuit for electric lamps is frequently retained within a housing having a unitary connection portion. Safety and standardization requirements in different jurisdictions vary and, respectively, may mandate integrated cable or wire connections from the accessory housing, or terminals for subsequent connection to externally supplied cables. Consequently, the connecting portion of the operating circuit may have either terminal clamps, such as terminal screws, snap-in or other terminal connectors, or may merely form a feed-through or lead-through arrangement for cables passing directly into the interior of the housing. Different arrangements of the housing, thus, were required, depending on whether cables or terminals were mandated by the user, or by safety and standardization requirements.